Eternal life traditionally refers to continued life after death, as outlined in Christian eschatology. The Apostles' Creed testifies: "I believe... the resurrection of the body, and life everlasting." In this view, eternal life commences after the second coming of Jesus and the resurrection of the dead, although in the New Testament's Johannine literature there are references to eternal life commencing in the earthly life of the believer, possibly indicating an inaugurated eschatology.
According to mainstream Christian theology, after death but before the Second Coming, the saved live with God in an intermediate state, but after the Second Coming, experience the physical resurrection of the dead and the physical recreation of a New Earth. The Catechism of the Catholic Church states, "By death the soul is separated from the body, but in the resurrection God will give incorruptible life to our body, transformed by reunion with our soul. Just as Christ is risen and lives for ever, so all of us will rise at the last day." N.T. Wright argues that "God's plan is not to abandon this world... Rather, he intends to remake it. And when he does, he will raise all people to new bodily life to live in it. That is the promise of the Christian gospel" 
In the Synoptic Gospels and the Pauline Letters, eternal life is generally regarded as a future experience, but the Gospel of John differs from them in its emphasis on eternal life as a "present possession".Raymond E. Brown points out that in the synoptic gospels eternal life is something received at the final judgment, or a future age (Mark 10:30, Matthew 18:8-9) but the Gospel of John positions eternal life as a present possibility, as in John 5:24.
Thus, unlike the synoptics, in the Gospel of John eternal life is not only futuristic, but also pertains to the present. In John, those who accept Christ can possess life "here and now" as well as in eternity, for they have "passed from death to life", as in John 5:24: "He who hears my word, and believes him that sent me, has eternal life, and comes not into judgment, but has passed out of death into life." In John, the purpose for the incarnation, death, resurrection and glorification of The Word was to provide eternal life to humanity.
Scholars such as John H. Leith assert that eternal life is never described in detail in the New Testament, although assurances are provided that the faithful will receive it. Other scholars such as D. A. Carson suggest that eternal life is explicitly defined in John 17:3, where Jesus says in his High Priestly Prayer, "Now this is eternal life: that they may know you, the only true God, and Jesus Christ, whom you have sent." Carson says of this verse that "Eternal life turns on nothing more and nothing less than knowledge of the true God" and that it is "not so much everlasting life as personal knowledge of the Everlasting One." The Eerdmans Dictionary of the Bible on the other hand, contends that "the nature of eternal life is only sketched in its essential elements in the New Testament".
John W. Ritenbaugh says that eternal life is knowing God, and that Jesus implies an intimate relationship with God that matures over time. 
While the Synoptic Gospels are seen as focusing on the proclamation of the Kingdom of God, some scholars see eternal life as the central theme of Jesus' preaching in the Gospel of John, where receiving eternal life is seen to be synonymous with entering the Kingdom. In Christian teachings, eternal life is not an inherent part of human existence, and is a unique gift from God, based on the model of the Resurrection of Jesus, viewed as a unique event through which death was conquered "once for all", permitting Christians to experience eternal life. This eternal life is provided to believers, generally assumed to be at the resurrection of the dead.
In New Testament theology, in addition to "life" (zoe, i.e. in Greek), there is also a promised spiritual life sometimes described by the adjective eternal (aionios i.e. ? in Greek) but other times simply referred to as "life". In both John and Paul the possibility of attaining eternal life and avoiding the wrath of God is dependent on believing in Jesus, the Son of God. For John abiding in Christ involves love for one another, as in John 15:9-17, and John 5:24. The existence of divine love in believers, then facilitates the influence of the gospel on the world, and lead to widespread salvation.1 John 3:14 then manifests "the already but not yet" acquisition of eternal life by referring to the acquisition of eternal life as a once for all (ephapax) event, and the role of love in attaining it: "We know that we have passed from death to life, because we love each other. Anyone who does not love remains in death", somewhat reminiscent of the words of Jesus in John 5:24.
In the Pauline epistles, the oldest texts in the New Testament, eternal life becomes possible in the person of Christ, where by the grace of God and through faith in Christ humans can receive the gift of eternal life. For Paul (as in Galatians 6:8) future eternal life arrives as a result of the indwelling of the Holy Spirit during the present life. Paul views sin as an obstacle to attaining eternal life, as in Romans 6:23. For Paul eternal life is a future possession and "the eschatological goal towards which believers strive." Paul emphasizes that eternal life is not merely something to be earned, but a gift from God, as in Romans 6:23: "wages of sin is death; but the free gift of God is eternal life in Christ Jesus our Lord." Romans 6:23 thus also counter-positions sin and eternal life: while sin results in death, those who are "in Christ" will reap eternal life.
Paul also discusses the relationship of eternal life to the Holy Spirit, stating that to be with the Spirit and to think with the Spirit leads to eternal life, e.g. Galatians 6:8: :"he who sows to the Spirit shall of the Spirit reap eternal life." For Paul future eternal life arrives as a result of the indwelling of the Holy Spirit during the present life, and the inter-related statements about the present life, the Spirit and future life form a key element of the teachings on the topic in Galatians.
1 Timothy 1:16 characterizes Christians by reference to eternal life and calls the followers of Jesus: "an ensample of them that should thereafter believe on him unto eternal life." and 6:12 advises them to "fight the good fight of the faith, lay hold on the life eternal".
There are parallels in how the synoptics refer to "being saved" and John refers to eternal life, as in the table below:
|Matthew 16:25||Mark 8:35||Luke 9:24||John 12:25|
|... whosoever shall lose his life for my sake shall find it.||... whosoever shall lose his life for my sake and the gospel's shall save it.||... whosoever shall lose his life for my sake, the same shall save it.||... he that hates his life in this world shall keep it unto life eternal.|
The Gospel of Matthew includes references to eternal life, in 19:16, 19:29 and 25:46. The reference in Matthew 19:16 is within the parable of Jesus and the rich young man which also appears in Mark 10:17-31 and Luke 18:18-30. This parable relates the term "eternal life" to entry into the Kingdom of God. The parable starts by a question to Jesus from the young man: "what good thing shall I do, that I may have eternal life?" and Jesus advises him to keep the commandments, and then refers to entry into the "Kingdom of God" in the same context.
For God so loved the world, that he gave his only begotten Son, that whosoever believeth on him should not perish, but have eternal life.-- John 3:16
The Johannine concept of eternal life differs from the synoptic view.Johannine writings specifically present the view of eternal life as not simply futuristic, but also pertaining to the present, so those who hear the words of Jesus and trust in Yaweh can possess life "here and now" as well as in eternity, for they have "passed from death to life", as in John 5:24. Overall, the New Testament balances the present and future with respect to eternal life: the believer has passed from death to eternal life, but this remains to be totally realized in the future.
There are about 37 uses of the word life in the Gospel of John, of which about half refer to eternal life. There are six appearances in 1 John. The concept so permeates Johannine writings that in many cases one may just read life as eternal life.
Reformed evangelical theologian D. A. Carson sees John 5:24 as giving the "strongest affirmation of inaugurated eschatology in the Fourth Gospel": it is not necessary for the believer to "wait until the last day to experience something of resurrection life."George Eldon Ladd points out that, like the Kingdom of God, eternal life is "not only an eschatological gift belonging to the Age to Come; it is also a gift to be received in the old aeon". In this context, the gift of eternal life in the old aeon in which sin and death are still present is contrasted with eternal life in the new aeon of life and righteousness, the World to Come to which the faithful will belong.
However, although as in John 3:16 God has provided the gift of eternal life to believers, the possibility of perishing () remains if one rejects Jesus. According to John 3:36, "He that believeth on the Son hath eternal life; but he that obeyeth not the Son shall not see life, but the wrath of God abideth on him."
Towards the end of the Gospel of John (20:31), the purpose of writing the Fourth Gospel is stated as: "so that you may believe that Jesus is the Christ, the Son of God, and that by believing you may have life in his name". This is often correlated to 1 John 5:13: "These things I have written to you who believe in the name of the Son of God, so that you may know that you have eternal life."
John's Gospel positions eternal life around the person of Jesus, the Christ. In the Johannine view Christ can reveal life to humans because he is life himself.1 John 1:2: "proclaim to you the eternal life, which was with the Father and was manifested to us" is compared to John 1:1: "and the Word was with God", referring to the pre-existence of Christ.
The term is used in the Gospel of John in the context of the Water of Life and John 4:14 states: "the water that I shall give him shall become in him a well of water springing up unto eternal life."
In John 6:51 Jesus states that: "he who eats my flesh and drinks my blood has eternal life, and I will raise him up at the last day." This has been transposed, not only into a relationship with Jesus in common with Christian Theology but also into the Eucharist as an element of obtaining eternal life. The Catechism of the Catholic Church (item 1212) teaches that Christians are born through the sacrament of Baptism and receive the "food of eternal life" in the Eucharist.
In John 10:27-28 Jesus states that: "My sheep hear my voice, and I know them, and they follow me: and I give unto them eternal life; and they shall never perish." This refers to the personal, heart to heart relationship the Christian is expected to have with Jesus.
Another use is in John 17:3: "And this is life eternal, that they should know thee the only true God, and him whom thou didst send, Jesus Christ", this usage relating to the "theme of life" in the Book of Revelation.
Catholic Christians teach that there is a supernatural realm called Purgatory where souls who have died in a state of grace but have yet to expiate venial sins or temporal punishments due to past sins are cleansed before they are admitted into Heaven.
Seventh-day Adventists believe that only God has immortality, and when a person dies, death is a state of unconscious sleep until the resurrection. They base this belief on biblical texts such as Ecclesiastes 9:5 which states "the dead know nothing", and 1 Thessalonians 4:13-18 which contains a description of the dead being raised from the grave at the second coming.
The text of Genesis 2:7 clearly states that God breathed into the formed man the "breath of life" and man became a living soul. He did not receive a living soul; he became one. The New King James Bible states that "man became a living being". According to the Scriptures, only man received life in this way from God. Because of this man is the only living creature to have a soul.
Of the many references to soul and spirit in the Bible, never once is either the soul or the spirit declared to be immortal, imperishable or eternal. Indeed, only God has immortality (1 Timothy 1:17; 6:16). Adventists teach that the resurrection of the righteous will take place at the second coming of Jesus, at which time they will be restored to life and taken to reside in Heaven.
Jehovah's Witnesses believe the word soul (nephesh or psykhe) as used in the Bible is a person, an animal, or the life a person or animal enjoys. Hence, the soul is not part of man, but is the whole man--man as a living being. Hence, when a person or animal dies, the soul dies, and death is a state of non-existence, based on Psalms 146:4, Ezekiel 18:4, and other passages.Hell (Hades) is not a place of fiery torment, but rather the common grave of humankind, a place of unconsciousness.
One group, referenced as "the little flock" of 144,000 people, will receive immortality and go to heaven to rule as Kings and Priests with Christ during the thousand years. As for the rest of humankind, after the final judgment, it is expected that the righteous will receive eternal life and live forever on an Earth turned into a paradise.
Those granted immortality in heaven are absolutely immortal and cannot die by any cause. Even God himself wouldn't be able to kill them. They teach that Jesus was the first to be rewarded with heavenly immortality, but that Revelation 7:4 and Revelation 14:1, 3 refer to a literal number (144,000) of additional people who will become "self-sustaining", that is, not needing anything outside themselves (food, sunlight, etc.) to maintain their own life.
They make a distinction between immortality and eternal life in that humans who have passed the final judgement and were rewarded "eternal life" can still technically lose that life and die if they were ever hypothetically sin at some future point in time, though they do not succumb to disease or old age, due to their living forever still being subject to obedience. They also still continue to be dependent on food, water, air, and such to maintain life. Nevertheless, those who pass that final test are "guaranteed" to remain faithful throughout all eternity due to the test being perfect and designed to eliminate those who would ever misuse their free will.
In Latter-day Saint (Mormonism) theology, the spirit and the body constitute the human soul. Whereas the human body is subject to death on earth, they believe that the spirit never ceases to exist and that one day the spirits and bodies of all mankind will be reunited again. This doctrine stems from their belief that the resurrection of Jesus Christ grants the universal gift of immortality to every human being.
Joseph Smith, Jr., the founder of the Latter Day Saint movement, provided a description of the afterlife based upon a vision he received, which is recorded in the Doctrine and Covenants. According to the 76th section of the LDS scripture, the afterlife consists of three degrees or kingdoms of glory, called the Celestial Kingdom, the Terrestrial Kingdom, and the Telestial Kingdom. Other Biblical scriptures speak of varying degrees of glory, such as : "There are also celestial bodies, and bodies terrestrial: but the glory of the celestial is one, and the glory of the terrestrial is another. There is one glory of the sun, and another glory of the moon, and another glory of the stars: for one star differeth from another star in glory."
The few who do not inherit any degree of glory (though they are resurrected) reside in a state called outer darkness, which, though not a degree of glory, is often discussed in this context. Only those known as the "Sons of Perdition" are condemned to this state.
The doctrine of conditional immortality states the human soul is naturally mortal, and that immortality is granted by God as a gift. The doctrine is a "significant minority evangelical view" that has "grown within evangelicalism in recent years".
Some sects who hold to the doctrine of baptismal regeneration also believe in a third realm called Limbo, which is the final destination of souls who have not been baptised, but who have been innocent of mortal sin. Souls in Limbo include unbaptised infants and those who lived virtuously but were never exposed to Christianity in their lifetimes. Christian Scientists believe that sin brought death, and that death will be overcome with the overcoming of sin.